The invention relates to a miniature axial fan particularly of an axially compact construction, having a central motor driving a rotor disk with a housing surrounding the rotor disk in which an interior housing wall on the inflow side is cylindrical and extends past the axial center of the housing and then this cylinder wall expands outwardly to the outlet side of the housing to produce an enlargement of the flow cross-section. The housing has webs extending inwardly from the outlet side of the housing that carry the central driving motor with the rotor disk. A number of blades are mounted on the rotor disk which numbers differs from the number of webs.
In the case of axial fans of such a small size, there is, in addition to the often required compactness, the requirement of a low noise level and of an air output that is sufficient for its use. Because of the given small outside dimensions that is not easy to achieve. In the range of these dimensions and below, there is therefore a struggle involving millimeters. If one parameter, one dimension is changed by a few millimeters in favor of one characteristic, this has a considerable effect on other characteristics and thus on the overall characteristics.
On the basis of the European Patent Application 0100078, an axial fan is known that is suitable for a rotor disk diameter of below 100 mm.
The invention is therefore based on the objective of developing a very small, relatively compact axial fan having a rotor disk driven by a concentric coaxial driving motor in such a way that, in the case of the small size offered here, it has a relatively good air output and a low noise level.
The invention is achieved by the means of a miniature axial fan, particularly of an axially compact construction, having a central motor driving a rotor disk with a housing surrounding the rotor disk in which an interior housing wall on the inflow side is cylindrical and extends past the axial center of the housing and then this cylinder wall expands outwardly to the outlet side of the housing to produce an enlargement of the flow cross-section. The housing has webs extending inwardly from the outlet side of the housing that carry the central driving motor with the rotor disk. A number of blades are mounted on the rotor disk which numbers differs from the number of webs. A rotor disk has a diameter of no more than 60 mm. The blades are designed in such a way that on the output side they have a large adjusting angle of 70.degree. to 90.degree. due, to the fact that when viewed in a top view, that is radial with respect to the axis of rotation onto the blade, the bend of the blade from the direction of the inlet side is at first slight and this bend then changes into a bend that becomes more extensive up to the blade edge on the outlet side.
These and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawings which show, for the purpose of illustration only, plural embodiments in accordance with the present invention, and wherein: